Z-Wave is a widely adopted, proprietary standard for wireless home control and automation. It enables an affordable set of Z-Wave products, which interoperate with each other regardless of brand. Each Z-Wave certified product has to pass a stringent conformance tests to assure it meets the Z-Wave standard for operation and interoperability with other Z-Wave certified devices and controls.
Z-Wave enabled products offer reliable, confirmable, 2-way control communications throughout the home, without the need for any new wiring or any complex programming. It has been designed for residential and light commercial applications such as lighting control, thermostats, garage doors and access control, security systems, blinds and curtains, Internet gateways, PC applications, media centre integration, and universal remote controls.
Z-Wave uses mesh networking technology to route 2-way command signals from one Z-Wave device to another, around any obstacles or radio dead spots that might occur throughout the home. The result is assured, reliable whole-house coverage, with confirmation messages. As more devices are added, the mesh network becomes more robust. There is a limit to the number of devices that can form a single mesh network but it is over 200. European Z-Wave devices operate at 868.42MHz making them incompatible with their US equivalents operating at 908.42MHz
There is a lot of open source activity underway that uses Z-Wave. The Open Z-wave group have a goal to create free software to interface with all available Z-Wave PC controllers, allowing anyone to create applications that manipulate and respond to devices on a Z-Wave network, without requiring in-depth knowledge of the Z-Wave protocol or the purchase of expensive development kits.
The Fibaro Home Center 2 is aimed at the higher end of the market, with a retail price of around £500.
Companies like MiCasaVerde have developed a the MiCasaVerde VERA2 Internet Gateway, which is a small box that connects to your Z-Wave enabled devices and the Internet. It can control lights, switches, plugs, thermostats, cameras, etc. It can be configured using a web browser (both within or outside of your home) or with the iVera iPhone app.
Somfa TaHomA is a system that uses both Z-Wave and Radio Technology Somfy (RTS).
A controller basically manages the network and the inclusion and exclusion of devices on it. Controllers can be simple dongles with software or a dedicated unit (hardware and software), such as the MiCasaVerde Vera.
Association is the process of linking Z-wave devices on a Z-wave network so that a device like a sensor can report reading and triggers to another Z-Wave device. Each Z-Wave device supporting Command Class Association can be associated with a slave device. This means that it can switch on/off or dim other devices.
A device is a mapping to a logical function (e.g. a switch or temperature sensor) on the Z-Wave network. Each node can have one or more devices associated with it and these are usually represented as child devices (e.g. the Everspring ST814 temperature and humidity sensor has 3 devices associated with it).
Exclusion is the process of removing a Z-wave device from a Z-wave network. The result is that it is no longer assigned a Node ID. Devices that are no longer part of the network or are switched off need to be excluded or attempts will be made to route messages via them.
This is the process of rebuilding the network from scratch, with each node reporting those it can see in range.
Inclusion is the process of adding a Z-wave device into a Z-wave network. The result is that it is assigned a Node ID.
A Z-Wave network is a mesh network and not all nodes on the network are close enough to enable direct communication between them. Neighbours are nodes that are in radio range of a particular device/node. Communication with other nodes that are not neighbours is achieved by neighbours acting as relays for communication with nodes that are not directly reachable. Note that battery powered devices do not act as relays/repeaters due to the power usage implications.
A node is a device/module with a Z-Wave radio. A single node may represent more than one device on the network as some devices are have multiple functions (e.g. temperature and humidity) and each function can be represented as a child device.
This is where the controller polls nodes/devices to get current data from them. Devices that use batteries cannot be polled as they generally go into a sleep mode to conserver battery power. Our mnay years of experience of real-time systems design tells us that polling is not a desirable thing. It is much better to have event driven systems.
In an ideal world a Z-Wave network would not require polling and all devices would report status back as events to the Z-wave controller. If this was the case, then polling would add no value but, unfortunately Lutron own some IPR in this space and not all Z-Wave device maufacturers license and implement this capability. The only way to know for sure is to disable polling and test each devices behaviour.
One of the strengths of a mesh network like Z-Wave, is that the network nodes can communicate with other nodes directly or via neighbours. This is acheived by nodes relaying messages on to other nodes that can't be reached directly. Typically there are several routes for these messages to take. Z-wave limits messages to being relayed a maximum of four times.
We are still trying to work out what this does exactly.
Once you've finished pairing your devices and put them in their final places, you are supposed to do a 'heal network', or 'repair network', which causes every Z-Wave node to discover which other Z-Wave nodes are in proximity so it can figure out what nodes to use to relay. This is called the routing table.
Control & Interfacing
Typically, Z-Wave is aimed at people wanting a complete home automation solution, based around this technology. There are gateways to enable hybrid technology solutions though. It is the hybrid technology solutions that are of particular interest to us, as we already have a comprehensive set of automation hardware wired into our home and have developed our own Home Control System (HCS).
USB / Serial Port
The most desirable way (in our opinion) to interface to a Z-Wave is to use a PC USB adaptor, such as the Aeon Labs Z-Stick-S2-EU. This also appears to be well supported by various vendors and much of the software.
An alternative to using direct Home Control System (HCS) (PC-based) control is to use a controller that is also an Internet gateway.
There are various Software Development Kits (SDKs) available to write applications using these types of devices. The official Z-Wave SDK from Zensys is very expensive. The full development kit is $7500 and the Software Development Kit is $3000.
There are several 'whole house' solutions using Z-Wave technology:
- IP Symcon
- Embedded Automation
There is also a useful list of Z-Wave software at the Software Dungeon.
There are several open source projects using the Z-Wave technology:
In order to download the software, you need Subversion.
zVirtualScenes is a software-based Z-Wave Scene Controller where you can create custom Z-Wave scenes to be played back via GUI, HTTP Commands or Smartphone. It is a certified LightSwitch server (see mobile apps below).
This is very interesting to us as it provides a standard HTTP interface that could be used instead of inter-process communication.
In our Home Control System (HCS) architecture we would like a Java API to the Z-Wave network. Whilst some projects have been started, there don't appear to be any completed to provide a Java SDK. This is not necessarily a problem as our architecture uses processes and inter-process communication and each process can be written in any language, so long as the inter-process communication is common.
In the Apple Apps Store and in the Google Marketplace there a number of mobile apps designed to support Z-Wave hardware. Most require specific hardware controllers though and won't necessarily be able to control the hardware that you may have already installed.
LightSwitch is a mobile app for iOS and Android devices that allows you to control your devices anywhere in the world. It works with a LightSwitch certified server (which must be running in your home).
Power Controller is an Android app.
It requires a ControlThink ThinkStick Z-Wave USB Adapter and also requires that you run the ZWave Commander Server on your windows PC.
MiCasaVerde Vera 3
In December 2011, Mi Casa Verde launched the Mi Casa Verde Vera 3, which is a small box that connects to your Z-Wave enabled devices and the Internet. It can control lights, switches, plugs, thermostats, cameras, etc. It can be configured using a web browser (both within or outside of your home) or with the iVera iPhone app.
As well as the Vera 3 above, Mi Casa Verde also announce the VeraLite device. In the VeraLite controller the Wi-Fi is removed. It is aimed at people like us with an existing router and makes the device more affordable. It features a built-in battery compartment, to simplify the inclusion of Z-Wave devices into your network. This device is of particular interest to us and looks like it will be the heart of our Z-Wave home automation.
Door / Window Contact Sensors
The Everspring HSM02 is the new replacement device (Nov 2012) for the SM103 below. It is a much more compact device at 70 × 11.5 × 44mm. To get down to this tiny size it now uses a CR2450 'coin' battery and technology to optimise battery life. They are now claimed to last 3 years (assuming 14 openings/closings per day). HSM02 datasheet (PDF). We are using these devices in our networked door project and our experiences have hilighted an issue with the battery status reported.
The Everspring SM103 provides information on whether a door or window is open or closed. The product consists of a magnetic element and a reed relay in main unit. This device uses three AAA 1.5V batteries. We have bought one of these as part of our initial Z-Wave project and are using two in our current home. These are used on doors, where it has not been possible to run wires. In both cases, we have hidden them out of site and used remote reed relays and magnets.
This sensor comes with various model numbers from FGK101 to FGK107, where the number is the colour designation.
Automated Home have written a detailed review of this sensor.
PIR Motion Sensors
There are many Z-Wave PIR sensors available and quite often they feature other sensor capabilities as well, such as illumination and temperature.
The Everspring SP814 is a PIR motion sensor with a detection range of 110½ x 10m at 1.8m mounting height. It has tamper proof protection and a low battery LED indication.
Temperature & Humdity Sensors
The Everspring ST814 is both desktop use or wall mountable. The device has a LCD display which either shows the temperature or the humidity. Four buttons allow to switch between minimum, maximum or actual values, humidity versus temperature and Fahrenheit versus Celsius. The device can report values via Z-Wave and allows the setting of trigger levels for direct control of other Z-Wave device when the measured value hits the trigger point. It uses three 1.5V AA batteries. We have bought one of these as part of our initial Z-Wave project.
Light Level Sensors
The Aeon Labs Multisensor is a battery-powered Z-Wave motion sensor, temperature sensor, humidity sensor and lighting sensor all in one package. The sensor will send radio signals up to 6 associated Z-Wave devices within its own Z-Wave network when the sensor detects IR changes in front of its viewing window. It can report immediate temperature, humidity and lighting levels at various timing intervals.
The Everspring SF812 is a wireless smoke detector.
We have yet to investigate these devices.
The Danfoss Living Connect is a Z-Wave connected thermostatic radiator valve.
Plug-In Appliance Modules
These are designed to plug into a standard wall socket and have the ability to switch inductive loads. A desirable feature on these devices is a manual switch to toggle lamps on or off. These modules work well with devices that are designed to plug into a standard mains socket.
The Everspring AN1573 is a plug-in appliance or lighting module for 240Vac and loads up to 16A. It works up to 100m outdoor and up to 30m indoors. It features a red LED showing current status within a button used for switching, inclusion, exclusion and association. We have bought one of these as part of our Z-Wave project
Plug-In Lighting Modules
These are designed to plug into a standard UK wall socket and some support dimming capability as well as on/off functionality. Typically, they have a lower load switching capability than plug-in appliance modules. A desirable feature on these devices is a manual switch to toggle lamps on or off.
Wall Plate Lighting Modules
Many Z-Wave modules for lighting are not installed in the light fittings themselves but are designed to be retro-fitted to existing homes and installed in the wall boxes for the light switches. These modules typically provide a manual switch and a Z-Wave control layer in parallel. The main difference between these modules are whether they require 3 wires (earth, live and neutral) or 2 wires (no neutral) to operate.
The Duwi Everlux Dimmer Set (2-wire) modules alloww lighting to be controlled in wall switches where there is no neutral wire.
Lighting Fitting Modules
We are still investigating Z-Wave modules that fit into the light fittings or alongside them.
Wall Plate Inserts
Fibaro modules are designed to be retrofitted behind existing light and appliance switches. Fibaro claim a 5-minute install time and there are 4 different types available: a universal dimmer, a motor controller for blinds and shutters and two relays to switch loads of 1.5Kw or 3Kw. We have bought one of these as part of our Z-Wave project.
The Fibaro FGS221 is a dual relay switch that is very small (42mm × 36mm × 15mm.) and is designed to mounted in a wall box, behind a switch plate.
The Fibaro FGS221 is the single relay switch equivalent of the above device.
The Fibaro FGD221 is the lighting dimmer.
One thing we have learnt from installing these kinds of devices is that in our new house build, deep wall/pattress boxes (45mm) are very desirable. Whilst they do fit behing MK Grid Plus switches in 25mm boxes, it is a bit of a squeeze.
Switches / Relayshttp://www.eguestcontrols.com/products/lighting-devices/lfm-20/
Locks & Security
Z-Wave satin nickel front door lock with key and keypad entry.
Sirens & Alarms
FortrezZ sell Z-Wave sirens with either a clear or red strobe lens.
Tagging, Tracking & Proximity
Discovered this device online, which looks interesting.
If you are a UK supplier of Z-Wave products and are not listed below, then please contact us.
- Vesternet - Home Automation Technology Series (part 2) - Z-Wave (21st Nov 2012)
- Our Z-Wave project
- Z-Wave World